Skip to content

Technical Explanation

A B-Rep model combines two fundamental elements:

  • Geometry, which defines the mathematical shapes of surfaces and curves (for example, planes, cylinders, or NURBS).
  • Topology, which defines the relationships and connectivity between these geometric entities — how faces meet at edges, and edges meet at vertices.

This combination allows a B-Rep to describe not just the shape of an object, but also its structure and continuity. Because it captures both geometry and topology, a B-Rep enables advanced modeling operations such as Boolean operations, fillets, offsets, and shelling.

B-Rep is the core data structure used by most geometry kernels that power CAD, CAE, and CAM software.

Applications and Industry Use Cases

B-Rep models are used wherever precise geometric representation is critical:

  • CAD / Mechanical Design – defining detailed 3D parts and assemblies.
  • Manufacturing & Fabrication – ensuring surface and volume accuracy for production.
  • Metrology – enabling surface-based inspection and measurement.
  • AEC / BIM – representing complex architectural and structural components.

These representations provide the level of accuracy required for engineering-grade workflows, where tolerances, intersections, and topology must be exact.

Challenges or Common Pitfalls

Converting between different B-Rep formats or between B-Rep and mesh representations can lead to data loss, particularly in topology and precision. 

Different geometry kernels (such as ACIS, CGM, or Parasolid) may store and interpret B-Rep data differently, resulting in interoperability challenges. 

Maintaining geometric continuity (G0, G1, G2) across connected surfaces is also a common difficulty when modifying or exchanging B-Rep data.

How Spatial Helps

Spatial SDKs are built around robust B-Rep modeling technology.

  • 3D ACIS Modeler and CGM Modeler both implement comprehensive B-Rep architectures, providing the foundation for precise solid and surface modeling.
  • 3D InterOp enables seamless data exchange between different B-Rep kernels and CAD formats while preserving geometric and topological integrity.

With these SDKs, software developers can confidently build applications that leverage accurate, reliable, and interoperable B-Rep models — from design to manufacturing.